I don’t think it is possible for love to fail.
I think that love in this world is always an achievement and when it ends, it just means that a victory lap can only go on for so long. We don’t think less of the skill of Spain’s football team just because next year they’ll no longer be the reigning World Cup champions. Well, they could win again, but it has no bearing, really, on whether 2010 was a good year for them.
Things don’t have to last forever as a prerequisite to them being worthwhile.
Love is difficult. Love involves two people with their own sets of desires, priorities and baggage. No one should feel bad that the default setting of competing egos isn’t harmony. I played hockey in high school, which I was terrible at. But I loved it so much. Getting accolades or succeeding at something is fun, but anything worth your blood/sweat/tears isn’t defined by whether you happen to be good at it.
Love isn’t a pass/fail, it’s an A for effort.
I think in order to believe that love can fail you have to believe that failure is a bad enough outcome to compensate for the good stuff love brought you. Failure isn’t that bad, really. You tried something and it didn’t work out, nothing is a more human experience than that. Usually failure feels like a sigh of relief because the opposite of failure is inaction. And then, you might as well be dead. Failure is an answer to a question you had the courage to ask.